Apparatus and methods for determination of gain factors for wireless communication transmission power

ABSTRACT

Apparatus and methods for wireless communication transmission power control are provided. Determination of gain factors and adjustments for physical channel reconfiguration in the context of transmission power control are addressed. Preferably, implementation is in conjunction with communication systems in which wireless communications are conducted between wireless transmit receive units (WTRUs) using multiple channels that are concurrently transmitted.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/301,679, filed Dec. 13, 2005, which is a continuation of both U.S.application Ser. No. 10/948,714, filed Sep. 23, 2004, now U.S. Pat. No.7,373,164 and U.S. application Ser. No. 10/948,944, filed Sep. 23, 2004,now U.S. Pat. No. 7,020,127. Both U.S. application Ser. No. 10/948,714and U.S. application Ser. No. 10/948,944 claim priority from ProvisionalApplication No. 60/506,522, filed on Sep. 26, 2003. All of theaforementioned applications are incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to apparatus and methods for wirelesscommunication transmission power control, particularly for communicationsystems that implement wireless communications between wireless transmitreceive units (WTRUs) using multiple channels that are concurrentlytransmitted. Determination of gain factors and adjustments for physicalchannel reconfiguration in the context of transmission power control areaddressed.

BACKGROUND

Wireless communication systems are well known in the art. Generally,such systems comprise communication stations, i.e. wirelesstransmit/receive units (WTRUs), which transmit and receive wirelesscommunication signals between each other. Depending upon the type ofsystem, communication stations typically are one of two types: basestations or subscriber WTRUs, which include mobile units.

In order to provide global connectivity for wireless systems, standardshave been developed and are being implemented. One current standard inwidespread use is known as Global System for Mobile Telecommunications(GSM). This is considered as a so-called Second Generation mobile radiosystem standard (2G) and was followed by its revision (2.5G). GPRS(General Packet Radio Service) and EDGE (Enhanced Data rates for GlobalEvolution) are examples of 2.5G technologies that offer relatively highspeed data service on top of (2G) GSM networks. Each one of thesestandards sought to improve upon the prior standard with additionalfeatures and enhancements. In January 1998, the EuropeanTelecommunications Standard Institute-Special Mobile Group (ETSI SMG)agreed on a radio access scheme for Third Generation Radio Systemscalled Universal Mobile Telecommunications Systems (UMTS). To furtherimplement the UMTS standard, the Third Generation Partnership Project(3GPP) was formed in December 1998. 3GPP continues to work on a commonthird generational mobile radio standard.

A typical UMTS system architecture in accordance with current 3GPPspecifications is depicted in FIG. 1. The UMTS network architectureincludes a Core Network (CN) interconnected with a UMTS TerrestrialRadio Access Network (UTRAN) via an interface known as Iu which isdefined in detail in the current publicly available 3GPP specificationdocuments. The UTRAN is configured to provide wireless telecommunicationservices to users through wireless transmit receive units (WTRUs), knownas User Equipments (UEs) in 3GPP, via a radio interface known as Uu. TheUTRAN has one or more Radio Network Controllers (RNCs) and basestations, known as Node Bs in 3GPP, which collectively provide for thegeographic coverage for wireless communications with UEs. One or moreNode Bs are connected to each RNC via an interface known as Iub in 3GPP.The UTRAN may have several groups of Node Bs connected to differentRNCs; two are shown in the example depicted in FIG. 1. Where more thanone RNC is provided in a UTRAN, inter-RNC communication is performed viaan Iur interface.

Communications external to the network components are performed by theNode Bs on a user level via the Uu interface and the CN on a networklevel via various CN connections to external systems.

A CN is responsible for routing information to its correct destination.For example, the CN may route voice traffic from a UE that is receivedby the UMTS via one of the Node Bs to a public switched telephonenetwork (PSTN) or packet data destined for the Internet. In 3GPP, the CNhas six major components: 1) a serving General Packet Radio Service(GPRS) support node; 2) a gateway GPRS support node; 3) a bordergateway; 4) a visitor location register; 5) a mobile services switchingcenter; and 6) a gateway mobile services switching center. The servingGPRS support node provides access to packet switched domains, such asthe Internet. The gateway GPRS support node is a gateway node forconnections to other networks. All data traffic going to otheroperator's networks or the internet goes through the gateway GPRSsupport node. The border gateway acts as a firewall to prevent attacksby intruders outside the network on subscribers within the networkrealm. The visitor location register is a current serving networks‘copy’ of subscriber data needed to provide services. This informationinitially comes from a database which administers mobile subscribers.The mobile services switching center is in charge of ‘circuit switched’connections from UMTS terminals to the network. The gateway mobileservices switching center implements routing functions required based oncurrent location of subscribers. The gateway mobile services switchingcenter also receives and administers connection requests fromsubscribers from external networks.

The RNCs generally control internal functions of the UTRAN. The RNCsalso provides intermediary services for communications having a localcomponent via a Uu interface connection with a Node B and an externalservice component via a connection between the CN and an externalsystem, for example overseas calls made from a cell phone in a domesticUMTS.

Typically a RNC oversees multiple base stations, manages radio resourceswithin the geographic area of wireless radio service coverage servicedby the Node Bs and controls the physical radio resources for the Uuinterface. In 3GPP, the Iu interface of an RNC provides two connectionsto the CN: one to a packet switched domain and the other to a circuitswitched domain. Other important functions of the RNCs includeconfidentiality and integrity protection.

In general, the primary function of base stations, such as Node Bs, isto provide a radio connection between the base stations' network and theWTRUs. Typically a base station emits common channel signals allowingnon-connected WTRUs to become synchronized with the base station'stiming. In 3GPP, a Node B performs the physical radio connection withthe UEs. The Node B receives signals over the Iub interface from the RNCthat control the radio signals transmitted by the Node B over the Uuinterface. The Uu radio interface of a 3GPP communications system usesTransport Channels (TrCH) for transfer of user data and signalingbetween UEs and Node Bs. The channels are generally designated as SharedChannels, i.e. channels concurrently available to more than one UE, ordedicated channels (DCHs) which are assigned for use with a particularUE during a wireless communication.

In many wireless communication systems, adaptive transmission powercontrol algorithms are used to control the transmission power of WTRUs.In such systems, many WTRUs may share the same radio frequency spectrum.When receiving a specific communication, all other communicationstransmitted on the same spectrum cause interference to the specificcommunication. As a result, increasing the transmission power level ofone communication degrades the signal quality of all othercommunications within that spectrum. However, reducing the transmissionpower level too far results in undesirable received signal quality, suchas measured by signal to interference ratios (SIRs) at the receivers.

Various methods of power control for wireless communication systems arewell known in the art. An example of an open loop power controltransmitter system for a wireless communication system is illustrated inFIG. 2. The purpose of such systems is to rapidly vary transmitter powerin the presence of a fading propagation channel and time-varyinginterference to minimize transmitter power while insuring that data isreceived at the remote end with acceptable quality.

In communication systems such as Third Generation Partnership Project(3GPP) Time Division Duplex (TDD) and Frequency Division Duplex (FDD)systems, multiple shared and dedicated channels of variable rate dataare combined for transmission. In 3GPP wideband CDMA (WCDMA) systems,power control is used as a link adaptation method. Dynamic power controlis applied for dedicated physical channels (DPCH), such that thetransmit power of the DPCHs is adjusted to achieve a quality of service(QoS) with a minimum transmit power level, thus limiting theinterference level within the system.

One conventional approach for power control is to divide transmissionpower control into separate processes, referred to as outer loop powercontrol (OLPC) and inner loop power control (ILPC). The power controlsystem is generally referred to as either open or closed dependent uponwhether the inner loop is open or closed. Typically for 3GPP systems foruplink communications, the outer loops of both types of systems areclosed loops. The inner loop in an example WCDMA open loop type ofsystem illustrated in FIG. 2 is an open loop.

In outer loop power control, the power level of a specific transmitteris typically based on a target, such as a target SIR value. As areceiver receives the transmissions, the quality of the received signalis measured. In 3GPP systems, the transmitted information is sent inunits of transport blocks (TBs) and the received signal quality can bemonitored on a block error rate (BLER) basis. The BLER is estimated bythe receiver, typically by a cyclic redundancy check (CRC) of the data.This estimated BLER is compared to a target quality requirement, such atarget BLER, representative of QoS requirements for the various types ofdata services on the channel. Based on the measured received signalquality, a target SIR adjustment control signal is generated and thetarget SIR is adjusted in response to these adjustment control signals.

In inner loop power control, the receiver compares a measurement of thereceived signal quality, such as SIR, to a threshold value. If the SIRexceeds the threshold, a transmit power command (TPC) to decrease thepower level is sent. If the SIR is below the threshold, a TPC toincrease the power level is sent. Typically, the TPC is multiplexed withdata in a dedicated channel to the transmitter. In response to receivedTPC, the transmitter changes its transmission power level.

Conventionally, the outer loop power control algorithm in a 3GPP systemsets an initial target SIR for each coded composite transport channel(CCTrCH) based on a required target BLER, using a fixed mapping betweenBLER and SIR, assuming a particular channel condition. A CCTrCH iscommonly employed for transmitting various services on a physicalwireless channel by multiplexing several transport channels (TrCHs),each service on its own TrCH. In order to monitor the BLER level on aCCTrCH basis, a reference transport channel (RTrCH) may be selectedamong the transport channels multiplexed on the considered CCTrCH.

Uplink power control for dedicated channels transmitted by WTRUs in a3GPP system typically consists of a closed outer loop and an open innerloop such as is the example illustrated in FIG. 2. The closed outer loopis responsible for determination of a SIR target for the uplinktransmission made by a particular WTRU. The initial value of SIR targetis determined by a Controlling RNC (C-RNC), and then can be adjusted bya Serving RNC (S-RNC) based on measurement of uplink CCTrCH quality. TheS-RNC then sends the update of the SIR target to the WTRU. The openinner loop calculates the uplink transmit power by the WTRU measuringthe serving cell's P-CCPCH received signal code power (RSCP) every frameand calculating pathloss between the Node B and the WTRU. Based on thepathloss and the UTRAN signaled values of SIR target and UL Timeslotinterference signal code power (ISCP) of the UL CCTrCH, the WTRUcalculates the transmit power of a dedicated physical channel(P_(DPCH)).

Each DPCH (DPCHi) of the CCTrCH is then separately weighted by a weightfactor γ_(i) which compensates for the different spreading factors usedby the different DPCHs. The DPCHs in each timeslot are then combinedusing complex addition.

After combination of physical channels, the CCTrCH gain factor β isapplied. The gain factor compensates for differences in transmit powerrequirements for different TFCs assigned to the CCTrCH: each TFCrepresents a different combination of data from each of the transportchannels of the Coded Composite Transport Channel (CCTrCH). Eachcombination can result in a different amount of repetition or puncturingapplied to each TrCH in the CCTrCH. Since puncturing/repetition affectsthe transmit power required to obtain a particular signal to noise ratio(Eb/N0), the gain factor applied depends on the TFC being used, i.e.each TFC of the CCTrCH has its own gain factor. The value for gainfactor β_(j) applies to the jth TFC of the CCTrCH. This process isillustrated conceptually in FIG. 3 where, for example, the dedicatedchannels DPCH1 and DPCH2 carry data of the jth TFC of TrCHs.

The β_(j) value can be explicitly signaled to the WTRU for each TFC_(j),or the radio resource control (RRC) in the RNC can indicate that the UEshould calculate β_(j) for each TFC based on an explicitly signaledvalue of a reference TFC. This calculation is conventionally done basedon the rate matching parameters and the number of resource units neededby the given TFC_(j) and the reference TFC, where a resource unit isdefined, for example, as one SF16 code. For physical channelconfigurations with SF 16 codes only, the number of resource units (RUs)is equal to the number of codes. For configurations with codes that arenot all SF 16, the number of RUs is the equivalent number of SF 16codes. Equivalency for each of the spreading factors is as follows: 1SF8 code=2 RUs, 1 SF4 code=4 RUs, 1 SF2 code=8 RUs, 1 SF 1 code=16 RUs.

The first method is referred to as “signaled gain factors” and thesecond as “computed gain factors”.

The conventional method for a subscriber WTRU to calculate β factorsbased on a reference TFC is provided is as follows:

Let β_(ref) denote the signaled gain factor for the reference TFC andβ_(j) denote the gain factor used for the j-th TFC.

Define the variable:

$K_{ref} = {\sum\limits_{i}\; {{RM}_{i} \times N_{i}}}$

-   -   where RM_(i) is the semi-static rate matching attribute for        transport channel i, N_(i) is the number of bits output from the        radio frame segmentation block for transport channel i and the        sum is taken over all the transport channels i in the reference        TFC.

Similarly, define the variable

$K_{j} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$

-   -   where the sum is taken over all the transport channels i in the        j-th TFC.

Moreover, define the variable

$L_{ref} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$

-   -   where SF_(i) is the spreading factor of DPCH i and the sum is        taken over all DPCH i used in the reference TFC.

Similarly, define the variable

$L_{j} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$

-   -   where the sum is taken over all DPCH i used in the j-th TFC.

The gain factor β_(j) for the j-th TFC is then conventionally computedas:

$\beta_{j} = {\sqrt{\frac{L_{ref}}{L_{j}}} \times \sqrt{\frac{K_{j}}{K_{ref}}}}$

Instead of sending a reference TFC, the values of the gain factor foreach TFC can be determined in the RNC and sent to the WTRU. However, thecurrent standards do not define how to determine the signaled gainfactor values that are to be sent to the WTRUs. The inventors haverecognized that the calculation of gain factors for TFCs can be improvedby making them proportional to the gain factor applicable to a referenceTFC. This improvement has applicability for both “signaled gain factors”and “computed gain factors”.

Another problem arising in conventional system relates to uplink powercontrol maintenance during reconfiguration. When physical channelreconfiguration changes the spreading factors used for a CCTrCH,puncturing/repetition for each TFC may be different before and after thereconfiguration. Since conventionally the gain factors depend on therelative puncturing/repetition among the TFCs, the gain factors usedbefore reconfiguration may be misaligned with the puncturing/repetitionafter reconfiguration.

The inventors have recognized that this leads to the need for powercontrol to re-converge based on the new puncturing/repetition of theTFCs. If new gain factors are computed or selected which do not resultin the same output power levels after reconfiguration relative topuncturing/repetition, re-convergence is required. To reduce the needfor re-convergence, the inventors have recognized that it would beadvantageous to:

-   -   select a reference TFC and a reference gain factor value which        will be appropriate before and after reconfiguration;    -   select a new reference TFC to use after reconfiguration        (reference gain factor remains the same before and after        reconfiguration);    -   select a new reference gain factor to use after reconfiguration        (reference TFC remains the same before and after        reconfiguration); and/or    -   select a new SIR target to use after reconfiguration.

SUMMARY

Apparatus and methods for determination of gain factors for wirelesscommunication transmission power control are provided. Preferably,implementation is in conjunction with communication systems in whichwireless communications are conducted between wireless transmit receiveunits (WTRUs) using multiple channels that are concurrently transmitted.

In one aspect of the invention, a method of transmission power controlfor a WTRU that transmits signals in a forward composite channelcarrying data in a selected combination of channels is provided wherethe WTRU is configured to make forward channel power adjustments as afunction of target metrics computed based on the data signals asreceived over the forward channel. A reference gain factor β_(ref) isdetermined for a reference combination of channels. A combination ofchannels is selected for data transmission on the forward compositechannel. When the selected combination of channels is not the same asthe reference combination of channels, a gain factor β for the selectedcombination of channels is computed such that the gain factor β for theselected combination of channels is proportional to the reference gainfactor β_(ref). The gain factor β for the selected combination ofchannels is then applied in making forward channel power adjustments tothe forward composite channel when transmitting data signals on theforward composite channel using the selected combination of channels.

Preferably, the WTRU is configured for use in a code division multipleaccess (CDMA) system, the data channels are transport channels (TrCHs),the composite channel is an uplink coded composite transport channel(CCTrCH) and a transport format combination (TFC) is associated witheach of a set of predefined format channel combinations of the CCTrCHwhere one of the format channel combinations is the referencecombination of channel, TFC_(ref). In such case, a jth combination ofchannels TFC_(j) is selected for data transmission on the forwardcomposite channel and a gain factor β_(j) is computed for the selectedcombination of channels such that: β_(j)=X×β_(ref). The gain factorβ_(j) can be computed by the WTRU or outside of the WTRU in which caseit is signaled to the WTRU. In the latter case, the gain factor ispreferably quantized before being signaled to the WTRU.

For implementation, a WTRU is provided that has a transmitter, receiverand an associated processor. The transmitter is preferably configured totransmit signals in a forward composite channel carrying communicationdata in a selected combination of channels. The receiver is preferablyconfigured to receive target metric data computed based on thecommunication data signals as received over the forward channel. Theprocessor associated is operatively with the transmitter and ispreferably configured to make forward channel power adjustments as afunction of received target metric data. The processor is preferablyconfigured to apply a gain factor for transmitter power control for acombination of channels that is selected for data transmission on theforward composite channel such that when the selected combination ofchannels is not the same as a reference combination of channels, thegain factor is computed for the selected combination of channels suchthat the gain factor for the selected combination of channels isproportional to a reference gain factor determined for the referencecombination of channels.

Preferably, the WTRU is configured for use in a code division multipleaccess (CDMA) system wherein the data channels are transport channels(TrCHs), the composite channel is an uplink coded composite transportchannel (CCTrCH) and a transport format combination (TFC) is associatedwith each of a set of predefined format channel combinations of theCCTrCH where one of the format channel combinations is the referencecombination of channel, TFC_(ref), having a reference gain factorβ_(ref) and a jth combination of channels TFC_(j) is the selectedchannel combination for data transmission on the forward compositechannel. In such case, the processor is preferably configured to applyand compute a gain factor β_(j) for the selected combination of channelsTFC_(j) such that β_(j)=X×β_(ref).

The invention includes the provision of a WTRU configured to assist intransmission power control for a transmitting unit that transmitssignals in a forward composite channel carrying communication data in aselected combination of channels where the transmitting unit isconfigured to make forward channel power adjustments as a function gainfactors determined by the WTRU. Such a WTRU preferably has a receiverconfigured to receive communication signals transmitted by thetransmitting unit in a selected combination of channels on the forwardcomposite channel along with a processor and a transmitter. Theprocessor is preferably configured to computed a gain factor β for theselected combination of channels received on the forward compositechannel such that the gain factor β is determined to be a reference gainfactor β_(ref) where the selected combination of channels is a referencecombination of channels or is otherwise computed to be proportional tothe reference gain factor β_(ref). The transmitter is preferablyconfigured to transmit data reflective of the gain factor β to thetransmitting unit to enable the transmitting unit to make forwardchannel power adjustments based thereon. Where the transmitting unit isconfigured to make forward channel power adjustments as a function oftarget metrics computed by the WTRU, the WTRU preferably has a processorconfigured to computed target metrics based on the data signals asreceived over the forward channel that is operatively associated withthe WTRU's transmitter such that computed target metric data istransmitted to the transmitting unit to enable the transmitting unit tomake forward channel power adjustments based thereon.

Such a WTRU is preferably configured as a network station for use in acode division multiple access (CDMA) system where the data channels aretransport channels (TrCHs), the composite channel is an uplink codedcomposite transport channel (CCTrCH) and a transport format combination(TFC) is associated with each of a set of predefined format channelcombinations of the CCTrCH where one of the format channel combinationsis the reference combination of channel, TFC_(ref). In such case, thenetwork station's processor is preferably configured to compute a gainfactor for the selected combination of channels such that when a jthcombination of channels TFC_(j) is the selected channel combination usedby the transmitting unit for data transmission on the forward compositechannel, where TFC_(j) is not TFC_(ref), a gain factor β_(j) is computedfor the selected combination of channels such that: β_(j)=X×β_(ref).Preferably, the processor is configured to quantize the gain factorβ_(j) and the transmitter is configured to transmit the quantized gainfactor β_(j) to the transmitting unit.

Another aspect of the invention provides, a method of transmission powercontrol for a WTRU that transmits communication signals in a forwardcomposite channel carrying data in a selected combination of channelswith respect to a selected physical transmission configuration of theforward composite channel. Communication signals are transmitted in theforward composite channel in a selected combination of channels withrespect to a first physical transmission configuration of the forwardcomposite channel. A reference combination of channels is determinedwith respect to the first physical transmission configuration of theforward composite channel. A gain factor β is applied to thetransmission of communication signals in the selected combination ofchannels with respect to the first physical transmission configurationof the forward composite channel where the gain factor β is determinedbased on spreading factors of the selected combination of channels andthe reference combination of channels with respect to the first physicaltransmission configuration of the forward composite channel. Thetransmission of communication signals in the forward composite channelis reconfigured to transmit the signals in a selected combination ofchannels with respect to a second physical transmission configuration ofthe forward composite channel. A reference combination of channels isdetermined with respect to the second physical transmissionconfiguration of the forward composite channel. A gain factor β′ isapplied to the transmission of communication signals in the selectedcombination of channels with respect to the second physical transmissionconfiguration of the forward composite channel where the gain factor β′is determined based on spreading factors of the selected combination ofchannels and the reference combination of channels with respect to thesecond physical transmission configuration of the forward compositechannel.

Where the WTRU is configured for use in a code division multiple access(CDMA) system, the data channels are transport channels (TrCHs) that mayhave different spreading factors for different physical configurationsof the composite channel, the composite channel is an uplink codedcomposite transport channel (CCTrCH) and a transport format combination(TFC) is associated with each of a set of predefined format channelcombinations of the CCTrCH defined for all physical configurations, thereference combination of channels with respect to the first physicaltransmission configuration of the forward composite channel ispreferably determined to be one of set of predefined format channelcombinations, TFC_(ref1), that has an associated gain factor β_(ref1).The reference combination of channels with respect to the secondphysical transmission configuration of the forward composite channel ispreferably determined to be one of set of predefined format channelcombinations, TFC_(ref2), that has an associated gain factor β_(ref2).

Where a common TFC that yields similar puncturing/repetition for thefirst and second physical channel configurations is identified, thecommon TFC is preferably determined to be the reference channelcombination TFC_(ref1) and also the reference channel combinationTFC_(ref2) and the gain factor β_(ref2) is selected to equal the gainfactor β_(ref1). As one alternative, reference channel combinationTFC_(ref2) can be determined by identifying a TFC that has similarpuncturing/repetition for the second physical channel configuration ascompared with puncturing/repetition of reference channel combinationTFC_(ref1) with respect to the first physical channel configuration andthe gain factor β_(ref2) is then selected to equal the gain factorβ_(ref1). As another alternative, the reference channel combinationTFC_(ref2) can be selected to be the same TFC as reference channelcombination TFC_(ref1) and the gain factor β_(ref2) is then selectedbased on the gain factor β_(ref1), and spreading factor changes in thereference channel combination from the first physical configuration tothe second physical configuration of the forward composite channel.

Preferably, a jth combination of channels TFC_(j) is selected for datatransmission with respect to the first physical transmissionconfiguration on the forward composite channel and a gain factor β_(j)is applied that is computed for the selected combination of channelssuch that: β_(j)=X*β_(ref1) where X is based upon spreading factors ofTFC_(j) and TFC_(ref1) with respect to the first physical transmissionconfiguration of the forward composite channel. Also, a kth combinationof channels TFC_(k) is preferably selected for data transmission withrespect to the second physical transmission configuration on the forwardcomposite channel and a gain factor β_(k) is applied that is computedfor the selected combination of channels such that: β_(k)=X′*β_(ref2)where X′ is based upon spreading factors of TFC_(k) and TFC_(ref2) withrespect to the second physical transmission configuration of the forwardcomposite channel.

For implementation, a WTRU is provided that has a transmitter, receiverand an associated processor. The transmitter is configured to transmitcommunication signals in a forward composite channel carrying data in aselected combination of channels with respect to a selected physicaltransmission configuration of the forward composite channel. Theprocessor is preferably configured to make forward channel poweradjustments as a function of target metrics computed based on the datasignals as received over the forward channel in conjunction withapplying a gain factor based on a reference combination of channels withrespect to the selected physical transmission configuration of theforward composite channel. The transmitter is preferably furtherconfigured to reconfigure the transmission of communication signals inthe forward composite channel from transmission in a first selectedcombination of channels with respect to a first physical transmissionconfiguration of the forward composite channel to transmission in asecond selected combination of channels with respect to a secondphysical transmission configuration of the forward composite channel.The processor is preferably further configured to compute and apply again factor to the transmission of communication signals in a selectedcombination of channels with respect to the respective physicaltransmission configuration of the forward composite channel such thatthe gain factor is determined based on spreading factors of the selectedcombination and a reference combination of channels with respect to therespective physical transmission configuration of the forward compositechannel.

Preferably, such a WTRU is configured for use in a code divisionmultiple access (CDMA) system where the data channels are transportchannels (TrCHs) that may have different spreading factors for differentphysical configurations of the composite channel, the composite channelis an uplink coded composite transport channel (CCTrCH) and a transportformat combination (TFC) is associated with each of a set of predefinedformat channel combinations of the CCTrCH defined for all physicalconfigurations. In such case the processor is preferably configured toselect a reference combination of channels, TFC_(ref1), with respect tothe first physical transmission configuration of the forward compositechannel from the set of predefined format channel combinations, that hasan associated gain factor β_(ref1) and a reference combination ofchannels, TFC_(ref2), with respect to the second physical transmissionconfiguration of the forward composite channel from the set ofpredefined format channel combinations that has an associated gainfactor β_(ref2).

The processor can be configured to identify a common TFC that yieldssimilar puncturing/repetition for the first and second physical channelconfigurations and to select the common TFC as the reference channelcombination TFC_(ref1) and also the reference channel combinationTFC_(ref2) and to select the gain factor β_(ref2) to equal the gainfactor β_(ref1). The processor can be configured to select the referencechannel combination TFC_(ref2) by identifying a TFC that has similarpuncturing/repetition for the second physical channel configuration ascompared with puncturing/repetition of reference channel combinationTFC_(ref1) with respect to the first physical channel configuration andto select the gain factor β_(ref2) to equal the gain factor β_(ref1).The processor can be configured to select the reference channelcombination TFC_(ref2) to be the same TFC as the reference channelcombination TFC_(ref1) and to compute the gain factor β_(ref2) based onthe gain factor β_(ref1) and spreading factor changes in the referencechannel combination from the first physical configuration to the secondphysical configuration of the forward composite channel. Where one ofthe format channel combinations is a selected reference combination ofchannel, TFC_(ref), and a jth combination of channels TFC_(j) is theselected channel combination for data transmission on the forwardcomposite channel, the processor is preferably configured to apply andcompute a gain factor β_(j) for the selected combination of channelsTFC_(j) such that: β_(j)=X×β_(ref).

An alternative method is provided for a WTRU that transmitscommunication signals in a forward composite channel carrying data in aselected combination of channels with respect to a selected physicaltransmission configuration of the forward composite channel where theWTRU is configured to make forward channel power adjustments as afunction of target metrics computed based on the data signals asreceived over the forward channel in conjunction with applying a gainfactor based on a reference combination of channels with respect to theselected physical transmission configuration of the forward compositechannel. A reference combination of channels is determined with respectto the forward composite channel. Communication signals are transmittedin the forward composite channel in a selected combination of channelswith respect to a first physical transmission configuration of theforward composite channel. The reference combination of channels of theforward composite channel is used for determining a gain factor to applyto the transmission of communication signals in the selected combinationof channels with respect to the first physical transmissionconfiguration of the forward composite channel. Forward channel poweradjustments are made as a function of target metrics computed based onthe data signals as received over the forward channel with respect tothe first physical transmission configuration of the forward compositechannel. The transmission of communication signals in the forwardcomposite channel are reconfigured to transmit the signals in a selectedcombination of channels with respect to a second physical transmissionconfiguration of the forward composite channel in conjunction withadjusting the forward channel transmission power based on an updatedtarget metric computed as a function of spreading factor changes in thereference channel combination from the first physical configuration tothe second physical configuration of the forward composite channel. Thereference combination of channels with respect to the second physicaltransmission configuration of the forward composite channel is used fordetermining a gain factor to apply to the transmission of communicationsignals in the selected combination of channels with respect to thesecond physical transmission configuration of the forward compositechannel.

Where the WTRU is configured for use in a code division multiple access(CDMA) system, the data channels are transport channels (TrCHs) that mayhave different spreading factors for different physical configurationsof the composite channel, the composite channel is an uplink codedcomposite transport channel (CCTrCH), a transport format combination(TFC) is associated with each of a set of predefined format channelcombinations of the CCTrCH defined for all physical configurations andSignal to Interference Ratio (SIR) metrics of the transmittedcommunication signals as received are used to compute a target SIR uponwhich forward channel power adjustments are based, the referencecombination of channels of the forward composite channel is preferablydetermined to be one of the set of predefined format channelcombinations, TFC_(ref), that has an associated gain factor β_(ref) andthe updated target metric used in adjusting the forward channeltransmission power in conjunction with reconfiguration is an updatedtarget SIR. The updated target SIR, SIR_target_(new), is preferablycomputed such that

${SIR\_ target}_{{new}\;} = {{SIR\_ target}_{old} + {10{\log \left( \frac{L_{{ref}\; 2}}{L_{{ref}\; 1}} \right)}}}$

where

-   -   SIR_target_(old) is the most recently used target metric for        making forward channel power adjustments with respect to the        first physical transmission configuration of the forward        composite channel;

$L_{{ref}\; 1} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$

-   -   where SF_(i) is a spreading factor of a dedicated physical        channel (DPCH) i with respect to the first physical        configuration and the sum is taken over all DPCH i used in        TFC_(ref); and

$L_{{ref}\; 2} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$

-   -   where SF_(i) is a spreading factor of a dedicated physical        channel (DPCH) i with respect to the second physical        configuration and the sum is taken over all DPCH i used in        TFC_(ref).

For implementation of such alternate method, a WTRU is provided that hasa transmitter, receiver and an associated processor. The transmitter isconfigured to transmit communication signals in a forward compositechannel carrying data in a selected combination of channels with respectto a selected physical transmission configuration of the forwardcomposite channel. The processor is preferably configured to makeforward channel power adjustments as a function of target metricscomputed based on the communication signals as received over the forwardchannel in conjunction with applying a gain factor based on a referencecombination of channels with respect to the selected physicaltransmission configuration of the forward composite channel. Thetransmitter is preferably further configured to reconfigure thetransmission of communication signals in the forward composite channelfrom transmission in a first selected combination of channels withrespect to a first physical transmission configuration of the forwardcomposite channel to transmission in a second selected combination ofchannels with respect to a second physical transmission configuration ofthe forward composite channel in conjunction with the processoradjusting the forward channel transmission power based on an updatedtarget metric computed as a function of spreading factor changes in thereference channel combination from the first physical configuration tothe second physical configuration of the forward composite channel. Theprocessor can be further configured to use the reference combination ofchannels of the forward composite channel for determining a gain factorβ to apply to the transmission of communication signals in selectedcombination of channels of the forward composite channel.

Preferably, such a WTRU is configured for use in a code divisionmultiple access (CDMA) system where the data channels are transportchannels (TrCHs) that may have different spreading factors for differentphysical configurations of the composite channel, the composite channelis an uplink coded composite transport channel (CCTrCH), a transportformat combination (TFC) is associated with each of a set of predefinedformat channel combinations of the CCTrCH defined for all physicalconfigurations, the reference combination of channels of the forwardcomposite channel, TFC_(ref), is one of the set of predefined formatchannel combinations and has an associated gain factor β_(ref) and whereSignal to Interference Ratio (SIR) metrics of the transmittedcommunication signals as received are used to compute a target SIR uponwhich forward channel power adjustments are based. The processor is thenpreferably configured to use an updated target SIR as the updated targetmetric used in adjusting the forward channel transmission power inconjunction with transmission reconfiguration. The processor can beconfigured such that, when a jth combination of channels TFC_(j) isselected for data transmission with respect to a current physicaltransmission configuration on the forward composite channel, a gainfactor β_(j) is computed and applied for the selected combination ofchannels such that: β_(j)=X*β_(ref) where X is based upon spreadingfactors of TFC_(j) and TFC_(ref) with respect to the current physicaltransmission configuration of the forward composite channel.

Other objects and advantages of the present invention will be apparentto persons skilled in the art from the following description andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is a schematic diagram of a typical CDMA system in accordancewith current 3GPP specifications.

FIG. 2 is a schematic diagram of an open loop power control system for awireless communication system which implements outer loop power controlvia a target SIR metric that can be configured in accordance with theteachings of the present invention.

FIG. 3 is a schematic illustration of a conventional combination ofphysical channels carrying data for the TrCHs of a jth TFC to which aCCTrCH gain factor is applied.

FIG. 4 is a table of Gain Factors for a first example for a firstconfiguration, Physical Configuration 1.

FIG. 5 is a table of Gain Factors for the first example for a secondconfiguration, Physical Configuration 2.

FIG. 6 is a comparative graph of Gain Factors when Using TFC3 as aReference for the first example.

FIG. 7 is a comparative graph of Gain Factor as a Function ofPuncturing/Repetition when Using TFC4 as a Reference TFC, β_(ref)=1 fora second example.

FIG. 8 is a comparative graph of Gain Factors as a Function ofPuncturing/Repetition when Using TFC10 as a Reference TFC, β_(ref)=1 fora third example.

FIG. 9 is a table of Gain Factors for the second and third examples forPhysical Configuration 1.

FIG. 10 is a table of Gain Factors for the second and third examples forPhysical Configuration 2.

FIG. 11 is a comparative graph of Gain Factor as a Function ofPuncturing/Repetition when Using TFC3 as a Reference for PhysicalConfiguration 1 and TFC6 as a Reference for Physical Configuration 2 fora fourth example.

FIG. 12 is a table of Gain Factors for the fourth example for PhysicalConfiguration 2.

FIG. 13 is a comparative graph of Gain Factor as a Function ofPuncturing/Repetition when Using TFC3 as a Reference for PhysicalConfiguration 1 and Physical Configuration 2 and β_(ref,new) computedfrom β_(ref,old) for a fifth example.

FIG. 14 is a table of Gain Factors for the fifth example for PhysicalConfiguration 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone (without the other features andelements of the preferred embodiments) or in various combinations withor without other features and elements of the present invention.

The present invention is described with reference to the drawing figureswherein like numerals represent like elements throughout. The terms basestation, wireless transmit/receive unit (WTRU) and mobile unit are usedin their general sense. The term base station as used herein includes,but is not limited to, a base station, Node-B, site controller, accesspoint, or other interfacing device in a wireless environment thatprovides WTRUs with wireless access to a network with which the basestation is associated.

The term WTRU as used herein includes, but is not limited to, userequipment (UE), mobile station, fixed or mobile subscriber unit, pager,or any other type of device capable of operating in a wirelessenvironment. WTRUs include personal communication devices, such asphones, video phones, and Internet ready phones that have networkconnections. In addition, WTRUs include portable personal computingdevices, such as PDAs and notebook computers with wireless modems thathave similar network capabilities. WTRUs that are portable or canotherwise change location are referred to as mobile units. Generically,base stations are also WTRUs.

Although the preferred embodiments are described in conjunction with athird generation partnership program (3GPP) code division multipleaccess (CDMA) system utilizing the time division duplex (TDD) mode, theembodiments are applicable to any wireless communication system thatutilizes multiple concurrent channels with dynamically controlledtransmission power. Additionally, the embodiments are applicable to CDMAsystems, in general, such as frequency division duplex (FDD) mode of a3GPP CDMA system.

Conventional power control methods for wireless systems such as 3GPPutilize so-called inner and outer loops. The power control system isreferred to as either open or closed dependent upon whether the innerloop is open or closed.

Pertinent portions of an open loop power control system having a“transmitting” communication station 10 and a “receiving” communicationstation 30 are shown in FIG. 2. Both stations 10, 30 are transceivers.Typically one is a base station, called a Node B in 3GPP, and the othera type of WTRU, called a user equipment UE in 3GPP. For clarity, onlyselected components are illustrated and the invention is described interms of a preferred 3GPP system, but the invention has application towireless communication systems in general, even such systems thatperform ad hoc networking where WTRUs communicate between themselves.Power control is important to maintain quality signaling for multipleusers without causing excessive interference.

The transmitting station 10 includes a transmitter 11 having a data line12 which transports a user data signal for transmission. The user datasignal is provided with a desired power level which is adjusted byapplying a transmit power adjustment from an output 13 of a processor 15to adjust the transmission power level. The user data is transmittedfrom an antenna system 14 of the transmitter 11.

A wireless radio signal 20 containing the transmitted data is receivedby the receiving station 30 via a receiving antenna system 31. Thereceiving antenna system will also receive interfering radio signals 21which impact on the quality of the received data. The receiving station30 includes an interference power measuring device 32 to which thereceived signal is input which device 32 outputs measured interferencepower data. The receiving station 30 also includes a data qualitymeasuring device 34 into which the received signal is also input whichdevice 34 produces a data quality signal. The data quality measuringdevice 34 is coupled with a processing device 36 which receives thesignal quality data and computes target signal to interference ratio(SIR) data based upon a user defined quality standard parameter receivedthrough an input 37.

The receiving station 30 also includes a transmitter 38 which is coupledwith the interference power measuring device 32 and the target SIRgenerating processor 36. The receiving station's transmitter 38 alsoincludes inputs 40, 41, 42 for user data, a reference signal, andreference signal transmit power data, respectively. The receivingstation 30 transmits its user data and the control related data andreferences signal via an associated antenna system 39.

The transmitting station 10 includes a receiver 16 and an associatedreceiving antenna system 17. The transmitting station's receiver 16receives the radio signal transmitted from the receiving station 30which includes the receiving station's user data 44 and the controlsignal and data 45 generated by the receiving station 30. Thetransmitting station's transmitter's processor 15 is associated with thetransmitting station's receiver 16 in order to compute a transmit poweradjustment. The transmitter 11 also includes a device 18 for measuringreceived reference signal power which device 18 is associated with pathloss computing circuitry 19.

In order to compute the transmit power adjustment, the processor 15receives data from a target SIR data input 22 which carries the targetSIR data generated by the receiver station's target SIR generatingprocessor 36, an interference power data input 23 which carries theinterference data generated by the receiving station's interferencepower measuring device 32, and a path loss data input 24 which carries apath loss signal that is the output of the path loss computing circuitry19. The path loss signal is generated by the path loss computingcircuitry 19 from data received via a reference signal transmit powerdata input 25 which carries the reference signal transmit power dataoriginating from the receiving station 30 and a measured referencesignal power input 26 which carries the output of the reference signalpower measuring device 18 of the transmitter 11. The reference signalmeasuring device 18 is coupled with the transmitting station's receiver16 to measure the power of the reference signal as received from thereceiving station's transmitter 38. The path loss computing circuitry 19preferably determines the path loss based upon the difference betweenthe known reference power signal strength conveyed by input 25 and themeasured received power strength conveyed by input 26.

Interference power data, reference signal power data and target SIRvalues are signaled to the transmitting station 10 at a ratesignificantly lower than the time-varying rate of the propagationchannel and interference. The “inner” loop is the portion of the systemwhich relies on the measured interface. The system is considered “openloop” because there is no feedback to the algorithm at a rate comparableto the time-varying rate of the propagation channel and interferenceindicating how good the estimates of minimum required transmitter powerare. If required transmit power level changes rapidly, the system cannotrespond accordingly to change the power adjustment in a timely manner.

With respect to the outer loop of the open loop power control system ofFIG. 2, at the remote receiver station 30, the quality of the receiveddata is evaluated via the measuring device 34. Typical metrics fordigital data quality are bit error rate and block error rate.Computation of these metrics requires data accumulated over periods oftime significantly longer than the period of the time-varyingpropagation channel and interference. For any given metric, there existsa theoretical relationship between the metric and received SIR. Whenenough data has been accumulated in the remote receiver to evaluate themetric, it is computed and compared with the desired metric(representing a desired quality of service) in processor 36 and anupdated target SIR is then output. The updated target SIR is that value(in theory) which applied in the transmitter inner loop would cause themeasured metric to converge to the desired value. Finally, the updatedtarget SIR is passed, via the receiving station transmitter 38 and thetransmitting station receiver 16, to the transmitter 11 for use in itsinner loop. The update rate of target SIR is bounded by the timerequired to accumulate the quality statistic and practical limits on thesignaling rate to the power-controlled transmitter.

In the context of a composite data channel that carries data fromvarious permissible combinations of data channels, such as a 3GPPCCTrCH, the processor 15 of the transmitting WTRU 10 is preferablyconfigured to compute transmit power by applying a gain factor β thatcorresponds to the specific combination of data channels for which datais then being transmitted via the composite channel. In accordance withthe teachings of the present invention, the gain factor for eachcombination of data channels is calculated to be proportional to thegain factor β_(ref) of a reference data channel combination, i.e. for ajth combination of data channels the corresponding gain factorβ_(j)=X*β_(ref), where X is another value that may be calculated basedon other variables.

The gain factor value may either be computed in the transmitting WTRU orin the receiving WTRU 30. In the latter case the gain factor is thensent to the transmitting WTRU 10 such as via input 42 of the receivingWTRU's transmitter 38 associated with a processing device 50 thatcalculates the gain factor.

For example, for a 3GPP uplink CCTrCH, where the transmitting WTRU 10 isa UE that is communicating with a UTRAN as the receiving WTRU, theprocessor is preferably be configured to calculates the transmit powerof the dedicated physical channel (PDPCH) associated with the CCTrCHbased on pathloss and the UTRAN signaled values of SIR target and ULTimeslot interference signal code power (ISCP) of the UL CCTrCH in aconventional manner. Each DPCH of the CCTrCH is also then preferablyseparately weighted by a conventional weight factor γ_(i) whichcompensates for the different spreading factors used by the differentDPCHs and, in each timeslot, then combined using complex addition asillustrated in FIG. 3 for two channels DPCH1 and DPCH2 and respectiveweight factors γ₁ and γ₂.

After combination of physical channels, the processor 15 then preferablyapplies a CCTrCH gain factor calculated in accordance with the teachingsof the present invention. Accordingly, where the CCTrCH has a referenceTFC, TFC_(ref), but is using a jth TFC, TFC_(j), a gain factor β_(j) isapplied that is proportional to a gain factor β_(ref) for the referenceTCF, TFC_(ref.), i.e. β_(j)=X×β_(ref).

The gain factor is also preferably based on rate matching parameters andthe number of resource units needed by the given TFC_(j) and thereference TFC, where a resource unit is defined, for example, as oneSF16 code. Accordingly, X is preferably selected in accordance with theconventional parameters as follows:

Define the variable:

$K_{ref} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$

-   -   where RM_(i) is the semi-static rate matching attribute for        transport channel i, N_(i) is the number of bits output from the        radio frame segmentation block for transport channel i and the        sum is taken over all the transport channels i in the reference        TFC.

Similarly, define the variable

$K_{j} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$

-   -   where the sum is taken over all the transport channels i in the        j-th TFC.

Moreover, define the variable

$L_{{ref}\;} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$

-   -   where SF_(i) is the spreading factor of DPCH i and the sum is        taken over all DPCH i used in the reference TFC.

Similarly, define the variable

$L_{j\;} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$

-   -   where the sum is taken over all DPCH i used in the j-th TFC.

The factor X for the j-th TFC is then preferably computed as:

$X = {\sqrt{\frac{L_{ref}}{L_{j}}} \times \sqrt{\frac{K_{j}}{K_{ref}}}}$

and the gain factor β_(j) that is applied by processor 15 for the CCTrCHwhen using the jth TFC is preferably calculated as:

$\beta_{j} = {\sqrt{\frac{L_{ref}}{L_{j}}} \times \sqrt{\frac{K_{j}}{K_{ref}}} \times \beta_{ref}}$

The same computation of the gain factor β_(j) is preferably used whendetermining for both “signaled gain factors” in the receiving WTRU 30and “computed gain factors” in the transmitting WTRU 10. However, indownlink transmissions in 3GPP CDMA systems, for example, only a fixedset of values can be signaled to a transmitting WTRU 10. Accordingly,for the UE “signaled gain factors”, where such limitations occur, aquantized gain value, i.e. β_(j) quantized, is preferably determined byprocessing device 50 and sent to the transmitting WTRU10. For a 3GPPCCTrCH, currently allowed quantized β-values are given in TS 25.331 andare shown in Table 1.

TABLE 1 Fixed Signaled Gain Factor Values Signalling value for β_(j)Quantized value β_(j) 15 16/8  14 15/8  13 14/8  12 13/8  11 12/8  1011/8  9 10/8  8 9/8 7 8/8 6 ⅞ 5 6/8 4 ⅝ 3 4/8 2 ⅜ 1 2/8 0 ⅛ Note thatthere are 16 possible quantized values, they are in between ⅛ and 2,with steps of ⅛.

In accordance with the teachings of the present invention, quantizedβ_(j) is preferably determined by first determining β_(j) as aproportional value of β_(ref) as described above. Accordingly, for a3GPP CCTrCH using the jth TFC preferably:

$\beta_{j} = {\sqrt{\frac{L_{ref}}{L_{j}}} \times \sqrt{\frac{K_{j}}{K_{ref}}} \times \beta_{ref}}$

The quantized β_(j) (β_(j) quantized) is then preferably determined asfollows:

$\beta_{j,{quantized}} = \left\{ \begin{matrix}{\frac{\left\lceil {8 \times \beta_{j}} \right\rceil}{8},} & {{{if}\mspace{14mu} \beta_{j}} < 2} \\{2,} & {{{if}\mspace{14mu} \beta_{j}} \geq 2}\end{matrix} \right.$

where ┌x┐ represents the smallest integer greater than or equal to x.This is a conservative approach that gives a value of β higher than theactual value calculated.

Examples of alternative preferred determinations of the quantized β_(j)(β_(j) quantized) include the following formulations:

$\begin{matrix}{\beta_{j,{quantized}} = \left\{ \begin{matrix}{0.125,} & {{{{if}\mspace{14mu} \beta_{j}} \leq 0.125}} \\{\frac{\left\lfloor {8 \times \beta_{j}} \right\rfloor}{8},} & {{{{if}\mspace{14mu} 0.125} < \beta_{j} < 2}} \\{2,} & {{{{if}\mspace{14mu} \beta_{j}} \geq 2}}\end{matrix} \right.} \\{or} \\{\beta_{j,{quantized}} = \left\{ \begin{matrix}{0.125,} & {{{{if}\mspace{14mu} \beta_{j}} \leq 0.125}} \\{\frac{\left\lfloor {{8 \times \beta_{j}} + 0.5} \right\rfloor}{8},} & {{{{if}\mspace{14mu} 0.125} < \beta_{j} < 2}} \\{2,} & {{{{if}\mspace{14mu} \beta_{j}} \geq 2}}\end{matrix} \right.} \\{or} \\{\beta_{j,{quantized}} = \left\{ \begin{matrix}{0.125,} & {{{{if}\mspace{14mu} \beta_{j}} \leq 0.125}} \\{\frac{\left\lfloor {8 \times \beta_{j}} \right\rfloor}{8},} & {{{{if}\mspace{14mu} 0.125} < \beta_{j} < 1}} \\{\frac{\left\lceil {8 \times \beta_{j}} \right\rceil}{8},} & {{{if}\mspace{14mu} 1} \leq \beta_{j} < 2} \\{2,} & {{{{if}\mspace{14mu} \beta_{j}} \geq 2}}\end{matrix} \right.} \\{or} \\{\beta_{j,{quantized}} = \left\{ \begin{matrix}{\frac{\left\lceil {8 \times \beta_{j}} \right\rceil}{8},} & {{{{if}\mspace{14mu} \beta_{j}} < 1}} \\{\frac{\left\lfloor {8 \times \beta_{j}} \right\rfloor}{8},} & {{{{if}\mspace{14mu} 1} \leq \beta_{j} < 2}} \\{2,} & {{{{if}\mspace{14mu} \beta_{j}} \geq 2}}\end{matrix} \right.}\end{matrix}$

where └x┘ represents the largest integer smaller than or equal to x. Inall the above formulations, gain factor values below 1/8 are preferablyrounded up to 1/8 and values above 2 are preferably rounded down to 2.For better performance, it is preferred that the reference TFC,TFC_(ref), be chosen so that all gain factor values are greater than 1/8and less than 2.

As another aspect of the invention, problems arising in power controlmaintenance during reconfiguration are hereafter addressed. As notedabove, the inventors have recognized the need for power control tore-converge based on new puncturing/repetition of TFCs. If new gainfactors are computed or selected which do not result in the same outputpower levels after reconfiguration relative to puncturing/repetition,re-convergence is required.

For example, DTX (Discontinuous Transmission) is conventionally appliedto 3GPP CCTrCHs mapped to dedicated and shared physical channels (PUSCH,PDSCH, UL DPCH and DL DPCH), when the total bit rate of the CCTrCHdiffers from the total channel bit rate of the physical channelsallocated to this CCTrCH. Rate matching is used in order to completelyfill physical channels that are only partially filled with data. In thecase that after rate matching and multiplexing no data at all is to betransmitted in a physical channel, that physical channel is discardedfrom transmission. When only part of the physical channels arediscarded, the CCTrCH is in partial DTX. When there is no data at all tosend, the CCTrCH is in DTX. In DTX the usage of special bursts applies.

Because of partial DTX, the puncturing/repetition depends not only onthe total number of resource units assigned, i.e. total data rate, butalso on the spreading factor of the physical channels assigned. Forexample, if a single physical channel with a spreading factor (SF) of 1is assigned to the CCTrCH (i.e., 16 resource units), even if the numberof bits to be sent is small, repetition will be performed to completelyfill that physical channel. If, instead, two physical channels with SFof 2 are assigned to the CCTrCH (similarly providing 16 resource units,8 per channel), where the bits to be sent all fit in one SF2 physicalchannel, the second physical channel is discarded. In this case thepercentage of repetition will be smaller than the case of a single SF1.Therefore, the amount of puncturing/repetition depends on the TFC beingused (number of bits to be sent) and the physical channel configuration.

The first time physical channels are configured for a CCTrCH, gainfactors are defined for each TFC in a transport format combination set(TFCS) for the CCTrCH. After successful physical channel establishment,an uplink outer power control algorithm converges to a given SIR target.This SIR target is based on gain factors currently configured for thatchannel (i.e., it is based on the amount of puncturing/repetition causedby that physical channel configuration).

During a physical channel reconfiguration procedure, there may be achange in the spreading factors, which may change thepuncturing/repetition for each TFC. If “computed gain factors” are used,and the reference TFC and the reference gain factor (β_(ref)) are keptthe same, the WTRU re-calculates the gain factor values for all TFCsbased on the old reference TFC and reference gain factor and the newphysical channel configuration. This can result in gain factors that donot yield the same output power relative to the puncturing/repetitionfor which power control has already converged.

If “signaled gain factors” are used, the RNC has two options: keep thesame gain factor values for all TFCs or send new gain factors. Unlessthe puncturing/repetition for each TFC before and after the newconfiguration is similar, keeping the gain factors the same will resultin the need for power control to re-converge. Accordingly, it would bepreferable to send new gain factors.

For the determination of new gain factors, it is advantageous tore-calculate the values based on a reference TFC to be proportional to areference gain factor β_(ref) as set forth above. Where the referenceTFC and the reference gain factor (β_(ref)) are kept the same, the gainfactor values for all TFCs based on the old reference TFC and referencegain factor and the new physical channel configuration preferably arere-calculated since changes are most likely to have occurred in the Xfactor which is preferably based on spreading factor and rate matchingparameters as set forth above. Similar to “computed gain factors”, thiscan result in gain factors that do not yield the same output powerrelative to the puncturing/repetition for which power control hasalready converged. Thus, the choice of the reference TFC and thereference gain factor value is extremely important for both “computedgain factors” and “signaled gain factors”.

The following example is illustrates how a reconfiguration can changethe relationship between the gain factor values (i.e., output power) andthe puncturing/repetition level. Although the gain factor valuespresented in the example are not quantized, the example applies for both“compute gain factors” or “signaled gain factors”. In uplink powercontrol for a 3GPP CCTrCH, signaled gain factors are preferablyquantized by the UTRAN before being signaled to a WTRU.

For simplicity, in this first example, β_(ref) is assumed to be equal toone and the Rate Matching attribute is assumed to be chosen to be thesame value for all transport channels of the CCTrCH. However, the sameproblems and solutions apply when β_(ref) is not one and when the RMattributes of the transport channels are not equal.

For illustrative purposes, this example selects an uplink configurationfor a 128 Kbps Radio Access Bearer (RAB) where the RAB is composed by a128 Kbps dedicated traffic channel (DTCH) and a 3.4 Kbps Signaling RadioBearer (SRB). The configuration of this RAB is shown in Tables 2 and 3and the TFCS for this CCTrCH is defined in Table 4.

TABLE 2 Transport channel configuration for UL128 kbps PS RAB HigherLayer RAB/Signalling RB RAB RLC Logical channel type DTCH RLC mode AMPayload sizes, bit 320 Max data rate, bps 128000 AMD PDU header, bit 16MAC MAC header, bit 0 MAC multiplexing N/A Layer 1 TrCH type DCH TBsizes, bit 336 TFS TF0, bits 0x336 TF1, bits 1x336 TF2, bits 2x336 TF3,bits 3x336 TF4, bits 4x336 TF5, bits 8x336 TTI, ms 20 Coding type TCCRC, bit 16 Max number of bits/TTI after 8460 channel coding Max numberof bits/radio frame 4230 before rate matching RM attribute* 120-160 *Arange of rate matching attributes is defined for each TrCH of the RAB.Since the ranges of the RM attribute of the DTCH and the SRB overlapfrom 155-160, the same value can be chosen for the two transportchannels as is assumed in this example for simplicity.

TABLE 4 TFCS For Example CCTrCH TFC (128 Kbps DTCH, SRB) TFC1 (TF1, TF0)TFC2 (TF2, TF0) TFC3 (TF3, TF0) TFC4 (TF4, TF0) TFC5 (TF5, TF0) TFC6(TF1, TF1) TFC7 (TF2, TF1) TFC8 (TF3, TF1) TFC9 (TF4, TF1) TFC10 (TF5,TF1)

TABLE 3 Transport channel configuration for UL 3.4 kbps SRB for DCCHHigher layer RAB/signalling RB SRB#1 SRB#2 SRB#3 SRB#4 User of RadioBearer NAS_DT NAS_DT High Low RRC RRC priority priority RLC Logicalchannel type DCCH DCCH DCCH DCCH RLC mode UM AM AM AM Payload sizes, bit136 128 128 128 Max data rate, bps 3400 3200 3200 3200 AMD/UMD PDUheader, bit 8 16 16 16 MAC MAC header, bit 4 4 4 4 MAC multiplexing 4logical channel multiplexing Layer 1 TrCH type DCH TB sizes, bit 148 TFSTF0, bits 0 × 148 TF1, bits 1 × 148 TTI, ms 40 Coding type CC ⅓ CRC, bit16 Max number of bits/TTI 516 before rate matching Max number ofbits/radio 129 frame before rate matching RM attribute 155-165

Two possible physical channel configurations are considered for thisfirst example CCTrCH as set forth in Table 5.

TABLE 5 Physical Channel Configurations For First Example PhysicalConfiguration 1 Physical Configuration 2 DPCH Midamble 256 chips 256chips Uplink Codes and time slots SF2 × 1 code × SF4 × 1 code × 1timeslot + SF16 × 2 timeslots + SF16 × 1 code × 1 time slot 1 code × 1time slot Max. Number of data 2340 bits 5376 bits bits/radio frame TFCIcode word 16 bits 16 bits TPC 2 bits 2 bits Puncturing Limit 0.52 0.52

Whether physical channel configuration 1 or 2 is used depends on cellavailability when the channel is configured, e.g., if one SF2 code isnot available, then two SF4 codes may be used instead.

For this first example, when the channel is configured for the firsttime, physical channel configuration 1 is used. Accordingly, the gainfactors are determined based on the physical channel configuration 1using the preferred formulation above. For the example, TFC3 is selectedas the reference TFC chosen is TFC3 and the table of FIG. 4 shows thegain factors for each TFC, accordingly.

If a reconfiguration is then required, new gain factors are calculated.For example, if reconfiguration is to physical configuration 2 and thereference TFC and the gain factor remain the same (i.e., TFC_(ref) isTFC3 and β_(ref)=1), the recalculated gain factors are shown in thetable of FIG. 5.

Gain factor as a function of puncturing/repetition for bothconfigurations when TFC3 is used as reference is shown in the graph ofFIG. 6. The gain factor values shown are not quantized. Quantization ofthe reference gain factor is not needed in case of “computed gainfactors”. In that case, the gain factor values determined by thetransmitting WTRU 10 are as shown in FIGS. 4 and 5. Quantization isneeded in case of “signaled gain factors” for an uplink 3GPP CCTrCH, inwhich case the values signaled would be the quantized version of thevalues shown in FIGS. 4 and 5 for this first example.

In this first example, in configuration 1, TFC3 yields 30% repetitionand, in configuration 2, TFC3 yields 35% puncturing, but the gain factorvalues are the same in both cases (i.e. equal to 1). If the uplink outerloop power control had converged for the beta values given for physicalchannel configuration 1, and the SIR target value is not updated duringreconfiguration, then a new convergence will be required. In this firstexample the power in configuration 2 is most likely be too low and SIRtarget is needed to increase.

Two solutions are provided as follows:

-   -   1. Intelligent selection of reference TFC: Maintain the SIR        target (send the latest value determined by the outer loop power        control algorithm to WTRU 10 in the reconfiguration message) and        -   a. maintain existing reference TFC and β_(ref) if the            original selection is chosen such that it will provide            similar output power levels for similar            puncturing/repetition in the new configuration of the            CCTrCH, or        -   b. select a new reference TFC or a new β_(ref).    -   2. Update the SIR target value based on changes of gain factor        values and send the SIR target value to the WTRU 10 in the        reconfiguration message. In this case β_(ref) will remain the        same, but the gain factor for all other TFCs in the TFCS may        change.

Intelligent selection of the reference TFC maintains the SIR target andintelligently selects the reference TFC and β_(ref). Three cases can beconsidered when the physical channels are reconfigured:

-   -   Case 1: Selection of reference TFC when all possible physical        configurations for the CCTrCH are known and there is a common        TFC that yields similar puncturing/repetition for all physical        channel configurations involved;    -   Case 2: Selection of reference TFC when all allowed        configurations are not known or when it is not possible to find        a common TFC that yields similar puncturing/repetition for all        physical channel configurations involved; and    -   Case 3: Selection of reference TFC when it is not possible to        find a TFC in the new configuration that yields similar        puncturing/repetition to that of the reference TFC in the old        configuration.

For the first case it is preferred to maintain the reference TFC and thereference gain factor value. In this case, the reference TFC is selectedto be one that has similar amount of puncturing/repetition for allconfigurations allowed to that CCTrCH. The same reference TFC andreference gain factor are used in all physical channel configurations ofthe CCTrCH. The reference TFC and reference gain factor are chosen whenthe channel is configured for the first time, and remain the same duringall following reconfigurations.

For the second case it is preferred to change the reference TFC andmaintain the reference gain factor value. In this case, a new referenceTFC is selected that has a similar puncturing/repetition to that of thereference TFC in the old configuration. Also, the gain factor β_(ref)for the new reference TFC remains the same during the reconfiguration.

For the third case it is preferred to maintain the reference TFC andchange the reference gain factor value. In this case, the same referenceTFC is used but the reference gain factor β_(ref) is changed. The newreference gain factor is determined by using as a reference the samereference TFC that was used in the old configuration.

For all of the cases above, even if the reference TFC and/or referencegain factor value β_(ref) remains the same, the gain factor values forall other TFCs in the TFCS are preferably recalculated as long as thereare changes in spreading factors (i.e., changes in the values of L_(j)).

Although less preferred, the usage of the selection process defined forCase 2 can be used in the scenario of Case 1 and the process defined inCase 3 can be used in the scenarios of either Case 1 or Case 2.

For TFCS reconfiguration employing intelligent selection, a firstpreferred alternative is to change the reference TFC and maintain thereference gain factor value. Preferably this is done by choosing the newreference TFC to be one that has a similar puncturing/repetition to thatof the reference TFC in the old configuration. The gain factor for thenew reference TFC then preferably remains the same during thereconfiguration. A second preferred alternative is to change thereference gain factor value. Preferably, the new reference TFC can beany TFC in the TFCS (the same as the old one or a different one). Thegain factor for the new reference TFC is preferably determined using asa reference, the β_(ref) that was used in the old configuration.

For the case of TFCS configuration, even if the reference TFC and/orreference gain factor value remains the same, the gain factor values forall other TFCs in the TFCS are preferably recalculated as long as thereare changes in the number of bits of a given transport channel (i.e.,changes in the values of K_(j)). However, in a case in which physicalchannel and/or TFCS reconfiguration results in similarpuncturing/repetition before and after reconfiguration, an acceptablealternative is to not update either the reference TFC or reference gainfactor.

For Case 1 above, when all possible physical channel configurations areknown in advance, the TFC that yields similar amount ofpuncturing/repetition for all configurations allowed to that CCTrCH ispreferably chosen as the reference TFC for all configurations. The gainfactor for the reference TFC (β_(ref)) are also preferably the same forall configurations.

In case of “computed gain factors”, the receiving WTRU 30 preferablysignals the reference TFC and the reference gain factor (β_(ref)) to thetransmitting WTRU 10 the first time the CCTrCH is configured. Thetransmitting WTRU 10 then calculate the gain factor for all other TFCsusing preferably the method provided above. Following a physical channelreconfiguration, the transmitting WTRU 10 uses the previously identifiedreference TFC and reference gain factor to calculate the new gainfactors for all the TFCs in the TFCS.

In case of “signaled gain factors” the receiving WTRU 30 preferably usesthe chosen reference TFC to determine the gain factor for all TFCs inthe TFCS and signals those values to the transmitting WTRU 10 the firsttime the CCTrCH is configured. For a 3GPP CCTrCH those values arepreferably quantized. The receiving WTRU 30 preferably uses the methoddescribed above to determine the gain factors for all other TFCs basedon the reference TFC. When a physical channel reconfiguration isperformed, the receiving WTRU 30 uses the previously identifiedreference TFC and reference gain factor to calculate the new gainfactors using updated X values for all the TFCs in the TFCS and signalsthe new gain factors to the transmitting WTRU 10.

For a 3GPP CCTrCH, the reference gain factor (β_(ref)) are preferably,any value from 1/8 to 2, with steps of 1/8. It is preferred that thereference TFC and the gain factor (β_(ref)) are chosen so that all gainfactor values for the other TFCs are greater than 1/8 and less than 2.Also, no change in the gain factors is needed if the physical channelreconfiguration does not change the spreading factors.

In the first example above, the reference TFC, TFC3 yields 30%repetition in physical configuration 1 and 35% puncturing in physicalconfiguration 2. However, TFC4 yields 3% puncturing in physicalconfiguration 1 and 1% repetition in physical configuration 2. Thevalues for TFC4 are much closer to each other than TFC3, and thereforeit would be preferred to choose TFC4 as reference TFC for the case 1scenario.

For the case 1 scenario, a modification of the first example is providedas a second example in connection with FIGS. 7, 9 and 10. Gain factor asa function of puncturing/repetition for both configurations 1 and 2 whenTFC4 is used as reference for the second example is shown in the graphof FIG. 7. Comparing the graph in FIG. 7 with the one shown in FIG. 6 weobserve that the two curves are much closer together.

Also for the case 1 scenario, a modification of the first example isprovided as a third example in connection with FIGS. 8, 9 and 10, whereTFC10 is chosen as a reference. TFC10 yields 46% puncturing in physicalconfiguration 1 and 45% puncturing in physical configuration 2. FIG. 8shows the gain factor as a function of puncturing/repetition for bothconfigurations when TFC10 is used as reference for a third example. Thefigure shows that similarly good results are obtained in this case.

Where either TFC4 or TFC10 is used as reference, the curve thatrepresents the gain factor as a function of puncturing/repetition forphysical configuration 2 overlaps the one for physical configuration 1.The gain factor value for a given puncturing/repetition is approximatelythe same for both configurations. The gain factor values shown are notquantized.

The tables of FIGS. 9 and 10 show the detailed results for the twophysical configurations, respectively, with respect to both the secondand third examples.

As for the first example, for simplicity in the second and thirdexamples, β_(ref) is chosen to be equal to one and the Rate Matchingattribute is assumed to be chosen to be the same value for all transportchannels of the CCTrCH. The same problems and solutions apply whenβ_(ref) is not one and when the RM attributes of the transport channelsare not equal.

The foregoing Case 1 solution is preferred only when all the possiblephysical configurations assigned to the CCTrCH are known in advance. Thesolution is simple when there are only two physical configurationsinvolved. If there are more than two configurations involved, it canbecome difficult to find a common TFC that results in similarpuncturing/repetition for all physical channel configurations involved.

For case 2, when the configurations are not known in advance, or when itis not possible to find a common TFC that yields similarpuncturing/repetition for all physical channel configurations involved,a new reference TFC is preferably chosen during reconfiguration. The newreference TFC chosen is preferably the one that has similarpuncturing/repetition to that of the reference TFC in the oldconfiguration. The gain factor for the new reference TFC (β_(ref))preferably remains the same during the reconfiguration.

In case of “computed gain factors”, the receiving WTRU 30 signalpreferably the new reference TFC and the (unchanged) reference gainfactor (β_(ref)) to the transmitting WTRU 10 in a reconfigurationmessage. Even though the reference gain factor does not change, it ispreferably sent in the reconfiguration message. In 3GPP, it is requiredto send a gain factor value when sending a reference TFC. Thetransmitting WTRU 10 then calculates the gain factor for all other TFCs.

In case of “signaled gain factors”, the receiving WTRU 30 preferablyuses the new chosen reference TFC and the (unchanged) reference gainfactor (β_(ref)) to determine the gain factor for all TFCs in the TFCSand signal those values, preferably quantized in the 3GPP context, tothe transmitting WTRU 10. In either case, gain factors are preferablycalculated using the preferred formulations disclosed above.

For the case 2 scenario, if TFC3 is chosen as reference for the initialconfiguration (configuration 1), the reference TFC in configuration 2 ispreferably selected as a TFC that yields around 30% repetition. A fourthexample based on a modification of the first example for case 2 isdescribed in connection with FIGS. 4, 11 and 12. The closest value toTFC3 is TFC6 that yields 56% repetition. This TFC has the same gainfactor as TFC3 had in physical configuration 1 (a gain factor equal to 1for the example given).

FIG. 11 shows the gain factor as a function of puncturing/repetition forboth configurations when TFC3 is used as reference in physical channelconfiguration 1 and TFC6 is used as reference in physical channelconfiguration 2 as the fourth example. The gain factor values shown arenot quantized. Because there is a relatively large difference betweenthe repetition in configuration 1 and 2 (26% difference), the two curvesare not as close as they were in the Case 1 examples illustrated in FIG.7 and FIG. 8, but they are still much better than the results shown inthe FIG. 6 graph reflective of the first example.

The table of FIG. 12 shows the detailed results for physicalconfiguration 2 when the reference TFC is TFC6 in this fourth example.This fourth example follows from the first example in which, forsimplicity, β_(ref) is chosen to be equal to one and the Rate Matchingattribute is assumed to be chosen to be the same value for all transportchannels of the CCTrCH. The same problems and solutions for case 2 applywhen β_(ref) is not one and when the RM attributes of the transportchannels are not equal.

For Case 3, when it is not possible to find a TFC in the newconfiguration that yields similar puncturing/repetition to that of thereference TFC in the old configuration, a new reference TFC ispreferably chosen during reconfiguration. The new reference TFC can beany TFC in the TFCS including the current reference TFC. The gain factorfor the new reference TFC (β_(ref,new)) is preferably determined usingas a reference the same reference that was used in the oldconfiguration, as follows:

$\beta_{{ref},{new}} = {\sqrt{\frac{L_{{ref},{old}}}{L_{{ref},{new}}}} \times \sqrt{\frac{K_{{ref},{new}}}{K_{{ref},{old}}}} \times \beta_{{ref},{old}}}$

i.e., the old configuration (old spreading factors), and the old β_(ref)are used as a reference to determine a new β_(ref).

Where the new reference TFC is chosen to be the same as the oldreference TFC, K_(ref,new)=K_(ref,old), and accordingly the preferredcalculation is then:

$\beta_{{ref},{new}} = {\sqrt{\frac{L_{{ref},{old}}}{L_{{ref},{new}}}} \times \beta_{{ref},{old}}}$

This new reference gain factor is used as a reference to determine thegain factors for all other TFCs in the new configuration. Accordingly,β_(ref,new) is used β_(ref) for calculating β_(j) gain factors for thejth TFC preferably using the preferred formulations above.

For the case 3 scenario, a further modification of the first example isprovided as a fifth example in connection with FIGS. 4, 13 and 14. Inthe fifth example, TFC3 is chosen as the new reference TFC, i.e., thesame as the old reference TFC in the first example. With physicalconfiguration 1 as the old configuration, physical configuration 2 asthe new configuration, and TFC3 as the old and new reference TFC:

L_(ref,old)=1/2 (physical configuration=SF2×1 code×1 timeslot)

L_(ref,new)=1/4 (physical configuration=SF4×1 code×1 timeslot)

β_(ref,old)=1

so:

$\beta_{{ref},{new}} = {{\sqrt{\frac{1/2}{1/4}} \times 1} = 1.41}$

FIG. 13 shows the gain factor as a function of puncturing/repetition forboth configurations for the case when TFC3 is used as reference inphysical configurations 1 and 2 and the new reference gain factor isdetermined for this fifth example. Comparing the graph of FIG. 13 withthe one shown in FIG. 6, it is observed that the two curves are muchcloser together, showing that the gain factor value for a givenpuncturing/repetition is approximately the same for both cases. In FIG.13, the curve for physical configuration 2 practically overlaps the onefor physical configuration 1 (i.e., the gain factor value for a givenpuncturing/repetition is approximately the same for bothconfigurations).

The table of FIG. 14 shows the detailed results for physicalconfiguration 2 when the new reference TFC remains as TFC3 and the newreference gain factor is determined from the old reference gain factoras in the fifth example.

The gain factor values are not quantized. For a 3GPP CCTrCH,quantization is necessary in order to send the values to thetransmitting WTRU 10, since the reference gain factor is not equal to 1or a multiple of 1/8. Thus, the gain factor values determined by thetransmitting WTRU 10 for all other TFCs for the case of “computed gainfactors” are slightly different from the values shown in this fifthexample. In case of “signaled gain factors”, all gain factor valuessignaled are preferably the quantized version of the values shown inthis fifth example for a 3GPP CCTrCH.

In case of “computed gain factors”, in order to minimize thequantization error, preferably the receiving WTRU 30 chooses the newreference TFC to be the one that will yield the new reference gainfactor whose unquantized value is closest to its quantized gain factorvalue.

The three cases discussed above assumed that the only parameters thatchanged in the TFCS during the TFCS reconfiguration are the gainfactors. There are cases in which there is a need to reconfigure thetransport formats thus affecting the data rate. In such cases, it isalso desirable to intelligently select a new reference TFC. Theselection is preferably done using the solutions presented in connectionwith the cases explained above.

In other words, there are two preferred choices during a TFCSreconfiguration. One preferred option is to choose the new reference TFCto be one that has a similar puncturing/repetition to that of thereference TFC in the old configuration. The gain factor for the newreference TFC (β_(ref)) should remain the same during thereconfiguration. This is similar to case 1 or 2 as illustrated by thesecond, third and fourth examples.

The other preferred option is to choose the new reference TFC to be anyTFC in the TFCS, including the old reference TFC. The gain factor forthe new reference TFC (β_(ref,new)) should be determined using as areference the same reference that was used in the old configuration, asfollows:

$\beta_{{ref},{new}} = {\sqrt{\frac{L_{{ref},{old}}}{L_{{ref},{new}}}} \times \sqrt{\frac{K_{{ref},{new}}}{K_{{ref},{old}}}} \times \beta_{{ref},{old}}}$

i.e., the old configuration (old spreading factors), and the old β_(ref)are used as a reference to determine a new β_(ref). Where the newreference TFC is chosen to be the same as the old reference TFC,K_(ref,new)=K_(ref,old), the calculation is simplified as:

$\beta_{{ref},{new}} = {\sqrt{\frac{L_{{ref},{old}}}{L_{{ref},{new}}}} \times \beta_{{ref},{old}}}$

The new reference gain factor is then used as a reference to determinethe gain factors for all other TFCs in the new configuration. This issimilar to case 3 as illustrated by the fifth example.

As an alternative to intelligent selection, the SIR target can beupdated during physical channel reconfiguration based on changes in gainfactors. In the above discussion of intelligent selection, the SIRTarget was not changed during reconfiguration, i.e., the latest updatefrom the UL outer loop power control algorithm is sent to thetransmitting WTRU 10 in the reconfiguration message. An alternativesolution described below entails an update of the SIR target duringphysical channel reconfiguration.

In this case, the reference TFC and the reference gain factor remain thesame during the physical channel reconfiguration. The SIR target isre-calculated based on changes that anticipated in the reference gainfactor value in order to maintain power control.

Preferably, the SIR target is updated as follows. Preferably, anadjustment factor β_(adj) is determined based on the gain factor β_(ref)for the reference TFC and the new physical channel configuration that isselected to maintain power control, as follows:

$\beta_{adj} = {\sqrt{\frac{L_{{ref}\; 1}}{L_{{ref}\; 2}}} \times \beta_{ref}}$

where

$L_{{ref}\; 1} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$

-   -   where SF_(i) is a spreading factor of a dedicated physical        channel (DPCH) i with respect to the first physical        configuration and the sum is taken over all DPCH i used in        TFC_(ref); and

$L_{{ref}\; 2} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$

-   -   where SF_(i) is a spreading factor of a dedicated physical        channel (DPCH) i with respect to the second physical        configuration and the sum is taken over all DPCH i used in        TFC_(ref).

The new SIR target is then given as:

$\quad\begin{matrix}{{SIR\_ target}_{new} = {{SIR\_ target}_{old} + {20{\log \left( \frac{\beta_{adj}}{\beta_{ref}} \right)}}}} \\{= {{SIR\_ target}_{old} + {10{\log \left( \frac{L_{{ref}\; 2}}{L_{{ref}\; 1}} \right)}}}}\end{matrix}$

In case the gain factor of the reference TFC of the old configurationwas set to 1, the new SIR target is given by a simplified expression as:

SIR_target_(new)=SIR_target_(old)+20 log(β_(adj))

The updated SIR Target is then sent to the transmitting WTRU 10 in areconfiguration message. The reference TFC and the reference gain factor(β_(ref)) remain the same, i.e. the adjustment factor β_(adj) is onlyused for determining the updated SIR Target, but is not thereafter usedas the gain factor.

In case of “computed gain factors”, there is no need to re-send thereference TFC and β_(ref) in the reconfiguration message, since theyremain the same. The transmitting WTRU 10 calculates the gain factorvalue for all other TFCs based on the old reference TFC and oldreference gain factor. The transmitting WTRU 10 preferably uses thepreferred formulations described above using the old reference gainfactor.

In case of “signaled gain factors”, during physical channelreconfiguration, the receiving WTRU 30 uses the reference TFC andβ_(ref) to determine the gain factor for all TFCs in the TFCS and signalthose values, preferably quantized for 3GPP CCTrCH context, to thetransmitting WTRU 10. The gain factor value for all other TFCs maychange due to the change in the physical channel configuration. Thereceiving WTRU 30 preferably uses the preferred formulations describedabove using the old reference gain factor.

For the case of “computed gain factors”, the update of the SIR targethas the advantage of minimizing signaling overhead, when compared to theintelligent selection methods presented above. Since the gain factorsare part of the transport channel configuration, in order to inform thetransmitting WTRU 10 of changes in these parameters, a “TransportChannel Reconfiguration” message has to be used, even if such changesare caused by a change in the physical channel configuration only. Incase there are no changes in the transport channel configuration, a“Physical Channel Reconfiguration” message can be used instead. Thismessage is preferred because it is shorter than the “Transport ChannelReconfiguration” message. For “computed gain factors”, if the update ofthe SIR target is used, then no change in the reference TFC or referencegain factor is needed, i.e., no changes in the transport channelconfiguration. In this case, a “Physical Channel Reconfiguration”message can be used to inform the transmitting WTRU 10 of thereconfiguration, and signaling overhead is minimized.

Preferably, the components to determine the gain factors and quantizedgain factors in either the transmitting WTRU 10 or receiving WTRU 30 areimplemented on a single integrated circuit, such as an applicationspecific integrated circuit (ASIC). However, the components may also bereadily implemented on multiple separate integrated circuits or insoftware on general purpose CPUs/DSPs.

While this invention has been particularly shown and described withreference to preferred embodiments, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the scope of the invention as describedhereinabove.

1. A method of transmission power control for a wireless transmit receive unit (WTRU) comprising: transmitting data signals on a select combination of channels of a composite channel where the selected combination of channels is a jth member of a set of at least j permitted combinations of channels that is not the same as a reference combination of channels; and said transmitting including applying a gain factor β_(j) such that β_(j)=X×β_(ref), where β_(ref) is a reference gain factor for the reference combination of channels, to adjust power of transmitted data signals on the composite channel using the selected combination of channels.
 2. The method of claim 1 wherein the gain factor β_(j) is computed by the WTRU.
 3. The method of claim 1 further comprising receiving signaling of the gain factor β_(j) by the WTRU.
 4. The method of claim 3 wherein the gain factor β_(j) is quantized before being signaled to the WTRU.
 5. The method of claim 1 wherein the applied gain factor β_(j) equals $\sqrt{\frac{L_{ref}}{L_{j}}} \times \sqrt{\frac{K_{j}}{K_{ref}}} \times \beta_{ref}$ where: $K_{ref} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$ where RM_(i) is a semi-static rate matching attribute for channel i, N_(i) is the number of bits output from a radio frame segmentation block for channel i and the sum is taken over all channels i in the reference combination of channels; $K_{j} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$ where the sum is taken over all channels i in the selected combination of channels; $L_{ref} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$ where SF_(i) is a spreading factor of a dedicated physical channel (DPCH) i and the sum is taken over all DPCH i used in the reference combination of channels; and $L_{j} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$ where the sum is taken over all DPCH i used in the selected combination of channels.
 6. The method of claim 5 wherein the gain factor β_(j) is computed by the WTRU.
 7. The method of claim 5 where the gain factor β_(j) is computed outside of the WTRU further comprising receiving signaling of the gain factor β_(j) by the WTRU.
 8. The method of claim 7 wherein the gain factor β_(j) is quantized before being signaled to the WTRU.
 9. The method of claim 8 wherein the reference combination of channels is chosen so that all gain factor values are greater than 1/8 and less than 2 and the quantized gain factor β_(j) (β_(j,quantized)) is determined as follows: $\beta_{j,{quantized}} = \left\{ \begin{matrix} {\frac{\left\lceil {8 \times \beta_{j}} \right\rceil}{8},} & {{{if}\mspace{14mu} \beta_{j}} < 2} \\ {2,} & {{{if}\mspace{14mu} \beta_{j}} \geq 2} \end{matrix} \right.$ where ┌x┐ represents the smallest integer greater than or equal to x.
 10. A wireless transmit receive unit (WTRU) comprising: a transmitter configured to transmit signals in a composite channel carrying communication data in selected channel combinations in connection with an application of a transmitter power control gain factor; and the transmitter configured to apply a gain factor β_(j) as the transmitter power control gain factor when transmitting data on a selected channel combination, that is a jth member of a set of at least j permitted channel combinations and that is not a reference combination of channels, such that β_(j)=X×β_(ref), where β_(ref) a gain factor used for the reference combination of channels.
 11. The WTRU of claim 10 further comprising a processor configured to compute the gain factor β_(j).
 12. The WTRU of claim 11 wherein the processor is configured to compute the gain factor β_(j) such that $\beta_{j} = {\sqrt{\frac{L_{ref}}{L_{j}}} \times \sqrt{\frac{K_{j}}{K_{ref}}} \times \beta_{ref}}$ where: $K_{ref} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$ where RM_(i) is a semi-static rate matching attribute for transport channel i, N_(i) is the number of bits output from a radio frame segmentation block for transport channel i and the sum is taken over all transport channels i in the reference combination of channels; $K_{j} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$ where the sum is taken over all transport channels i in the selected combination of channels; $L_{ref} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$ where SF_(i) is a spreading factor of a dedicated physical channel (DPCH) i and the sum is taken over all DPCH i used in the reference combination of channels; and $L_{j} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$ where the sum is taken over all DPCH i used in the selected combination of channels.
 13. The WTRU of claim 10 further comprising a receiver configured to receive signaling of the gain factor β_(j).
 14. The WTRU of claim 10 further comprising a receiver configured to receive signaling of the gain factor β_(j). wherein the gain factor β_(j) equals $\sqrt{\frac{L_{ref}}{L_{j}}} \times \sqrt{\frac{K_{j}}{K_{ref}}} \times \beta_{ref}$ where: $K_{ref} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$ where RM_(i) is a semi-static rate matching attribute for channel i, N_(i) is the number of bits output from a radio frame segmentation block for channel i and the sum is taken over all channels i in the reference combination of channels; $K_{j} = {\sum\limits_{i}{{RM}_{i} \times N_{i}}}$ where the sum is taken over all channels i in the selected combination of channels; $L_{ref} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$ where SF_(i) is a spreading factor of a dedicated physical channel (DPCH) i and the sum is taken over all DPCH i used in the reference combination of channels; and $L_{j} = {\sum\limits_{i}\frac{1}{{SF}_{i}}}$ where the sum is taken over all DPCH i used in the selected combination of channels.
 15. The WTRU of claim 10 further comprising a receiver configured to receive signaling of the gain factor β_(j) that has been quantized.
 16. The WTRU of claim 10 further comprising a receiver configured to receive signaling of the gain factor β_(j) that has been quantized wherein the reference combination of channels is chosen so that all gain factor values are greater than 1/8 and less than 2 and the quantized gain factor β_(j) (β_(j,quantized)) was determined as follows: $\beta_{j,{quantized}} = \left\{ \begin{matrix} {\frac{\left\lceil {8 \times \beta_{j}} \right\rceil}{8},} & {{{if}\mspace{14mu} \beta_{j}} < 2} \\ {2,} & {{{if}\mspace{14mu} \beta_{j}} \geq 2} \end{matrix} \right.$ where ┌x┌ represents the smallest integer greater than or equal to x. 